1. Field of the Invention
The present invention relates to a high voltage power supply control apparatus used in an electrophotographic mechanism section having a photosensitive body in a copying machine, a laser printer, or the like.
2. Description of the Related Art
An electrophotographic mechanism section used in a copying machine, a laser printer, or the like comprises, e.g., a photosensitive drum. After a photosensitive body of the photosensitive drum is charged by a charging unit, the photosensitive body is exposed by an exposure unit to form an electrostatic latent image on the photosensitive body. A toner is applied to the electrostatic latent image by a developer unit to form a toner image. The toner image is transferred onto transfer paper by a transfer unit.
The electrophotographic mechanism section comprises a high voltage power supply controlling apparatus for applying a high voltage to a charger in the charging unit, a developer sleeve in the developer unit, and a transfer charger in the transfer unit.
In this apparatus, however, since PWM (pulse-width modulation) controllers and A/D (analog-to-digital) converters are arranged in correspondence with charging, transferring, and biasing sections, the number of circuit members to be used is undesirably increased, and the apparatus become bulky. Since the PWM controllers are independently operated, each PWM controller suffers from a long operation rest period, resulting in poor operation efficiency.